Norse colonization of North Atlantic islands in the 1st millennium of the Common Era led to drastic prehistoric environmental changes in these previously “pristine” landscapes. In Iceland, Norse settlement is associated with a rapid decline in birch trees and heightened soil erosion, yet the timing of Norse exploration in the North Atlantic coincided with large climate changes that also influenced Icelandic environments. To date, there are few records that disentangle climatic and human impacts on terrestrial ecosystems, and there has been very little work on the impacts of Norse arrival on Iceland’s aquatic ecosystems. Here we use a high-resolution lake-sediment record from Vestra Gíslholtsvatn (VGHV), southwest Iceland to investigate these processes during the last 2,000 years. Norse arrival (c. 870 CE) in Iceland is followed by a rapid increase in sedimentation rate and a transition in leaf wax n-alkanes indicating a decrease in trees and expansion of grasses. This transition coincides with limnological changes, including increased primary productivity (i.e. C17n-alkane and biogenic opal fluxes) and shifts in the haptophyte algal community. Many of these changes are still apparent today. Comparisons with a new winter-spring alkenone temperature reconstruction from VGHV and marine sea surface temperature records show little to no correlation between terrestrial and aquatic ecological changes and climate at this time. Similarly, volcanic eruptions recorded in VGHV are not associated with any long-term environmental changes. Rather, the VGHV record suggests that human settlement had a lasting impact on the catchment area of VGHV and changes within the lake ecosystem.

中文翻译：

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北欧人定居对冰岛西南部陆地和水生生态系统的影响

在共同时代的第一个千年，北欧人对北大西洋岛屿的殖民导致这些以前“原始”景观发生剧烈的史前环境变化。在冰岛，北欧人定居与桦树的迅速减少和土壤侵蚀加剧有关，但北欧人在北大西洋探险的时机恰逢巨大的气候变化，这也影响了冰岛的环境。迄今为止，很少有记录将气候和人类对陆地生态系统的影响分开，而且关于北欧人抵达冰岛水生生态系统的影响的工作也很少。在这里，我们使用冰岛西南部 Vestra Gíslholtsvatn (VGHV) 的高分辨率湖泊沉积物记录来调查过去 2000 年的这些过程。北欧人到达（c。公元 870 年）在冰岛之后是沉降速率的快速增加和叶蜡正烷烃的转变，表明树木的减少和草的扩张。这种转变与湖沼学变化同时发生，包括初级生产力（即 C17n-烷烃和生物蛋白石通量）的增加和触藻藻群的变化。许多这些变化今天仍然很明显。与从 VGHV 和海洋海面温度记录重建的新冬春季烯酮温度的比较显示，此时陆地和水生生态变化与气候之间几乎没有相关性。同样，VGHV 中记录的火山喷发与任何长期环境变化无关。相当，